In many processes it is necessary to separate gases from a gas-liquid mixture. For instance, in some pump-operated installations, such as heating and cooling water installations, the circulator pump conveys a certain amount of gas with the liquid. This gas can lead to difficulties in both the installation and pump. This applies especially in the case of hot water central heating systems where air situated in the system is the cause of many problems. U.K. Patent application GB-2,082,942, published Mar. 17, 1992, describes a device for removing gas from a liquid that includes a separation chamber situated between entry and exit pipes. As the gas-liquid mixture is fed into the chamber with a twisting motion, the gas in the centrifugal field of the flow is forced toward the center of rotation which is on the center line of the chamber and passes to an outlet opening while the degassed liquid flows away to the exit pipe at the circumference of the chamber. The device also has a sieve tube arranged coaxially in the chamber which separates the gas from the liquid. The gas is continuously discharged into the atmosphere or into a separate storage unit.
Another device which relies on centrifugal separation is described in U.S. Pat. No. 3,603,062, issued Sept. 7, 1971. This apparatus is a high-capacity gas centrifugal separator adapted to receive a gas-liquid mixture and for creating a gas vortex surrounded by a liquid vortex. The separator includes a primary discharge passage for receiving liquid from the liquid vortex and having means for arresting the rotary motion of the separated liquid and a secondary discharge passage having means for separating the gas and liquid from the boundary layer between the gas and liquid vortices in the separator.
Screen-type separators are found in U.S. Pat. No. 4,976,754, issued Dec. 11, 1990, which describes a liquid line trap for non-condensable gases which comprises an outer cylindrical tube and a mesh inner tube axially positioned within the outer tube. The capillary action of the mesh tube traps non-condensable gas within an annular space between the inner and outer tubes. The separated liquid flows radially inward and through the mesh inner tube which has an outlet for the liquid. The trap can operate under zero gravity as well as normal ambient conditions. Finally, U.S. Pat. No. 4,537,740, issued Aug. 27, 1985, describes a device for collecting fission gas that has been released into coolant. The device uses filters for gas bubble separation wherein the surface tension in the pores of the filters prevents entrained gas bubbles from passing through the filters.
Despite the existence of these conventional gas-liquid separation devices, there is a need for a gas-liquid separation device that efficiently separates trace quantities of a gas forming component from a liquid mixture. Furthermore, the device preferably can begin separation even before the component forms gas bubbles in the mixture.